The proposed project will result in development and testing of a microcomputer based video image comparator for use in a clinical dermatological environment. This device will be used by dermatologists to ease the task of locating new or changed cutaneous lesions which may pose a lethal threat to the patient. In addition to easing the screening task it will result in greater uniformity and objectivity of patient examination. This is a completely innovative product for the clinical environment with considerable commercial potential. During the phase I project will build the prototype video comparator which will then be subjected to a series of receiver operating characteristic tests in well controlled experiments; it will be used to provide a demonstration of techniques for further enhancing the design, and it will be used in actual clinical environments to establish its ease of use. Development of a product from this prototype is quite feasible. The concept for this prototype has arisen from a market need expressed by dermatologists. The proposed product is significant in that it addresses a more effective means of early identification of serious, potentially rapidly evolving lesions.